Currently, in the field of Thin Film Transistor-Liquid crystal display (TFT-LCD) technology, with the continuous updating of technology, LCD panels are developing rapidly towards large size.
In an Advanced Super Dimension Switch (AD-SDS, ADS for short) technology, a multi-dimensional electric field is formed of an electric field generated at edges of slit electrodes in the same plane and an electric field generated between a slit electrode layer and a plate electrode layer, and the multi-dimensional electric field enables liquid crystal molecules at all orientations both between the slit electrodes and right above the electrodes in a liquid crystal cell to rotate, thus enhancing work efficiency of liquid crystal and improving light transmittance. The ADS technology can improve picture quality of a TFT-LCD product and possesses advantages of high resolution, high transmittance, low power consumption, wide viewing angle, high aperture ratio, low chromatic aberration, no push Mura and the like.
As shown in FIG. 1, in an array substrate of an Advanced Super Dimension Switch mode (ADS-mode) LCD panel of the prior art, an area defined by two adjacent gate lines 1 and two adjacent data lines 2 is one pixel unit. In each pixel unit, a pixel electrode and a common electrode 4 corresponding thereto are included (only the common electrode 4 is shown in FIG. 1), the pixel electrode may be disposed above the common electrode 4 and an insulation layer is disposed between the pixel electrode and the common electrode 4. In displaying, a voltage of the pixel electrode is controlled by changing electrical signals applied to the gate line 1 and the data line 2, and a common voltage is applied to the common electrode 4 through a common electrode line 3, so that an electric field is generated between the pixel electrode and the common electrode 4 so as to control the rotation of liquid crystal.
In the prior art, the common electrode lines 3 and the gate lines 1 are arranged parallel to each other, and such arrangement may result in overlap capacitance between the common electrode lines 3 and the data lines 2 and further lead to crosstalk phenomenon. In addition, coupling capacitance exists between the data lines 2 and the common electrodes 4, and in this case, crosstalk is caused by data signals to the voltages of the common electrodes 4, which affects the uniformity and stability of the voltages of the common electrodes, and in turn affects the actual voltages applied to the liquid crystal and affects a display picture. With the continuous increase in size of the LCD panel, the uniformity and stability of the voltages of the common electrodes inside the LCD panel become important factors influencing picture quality of a large-size LCD panel. Instability of the voltages of the common electrodes may result in degradation in performance of the panel, for example, some phenomena such as greenish phenomenon and crosstalk phenomenon may occur. The greenish phenomenon refers to a phenomenon that under a certain display picture, since variations in voltages of the common electrodes due to data pulses on the pixel electrodes cannot cancel each other out, brightness of green pixels is increased to present a greenish colour. The crosstalk phenomenon is generated due to the overlap capacitance existing between the common electrode lines and the data lines.
In the prior art, the voltages applied to the common electrodes are adjusted in real time by designing and regulating a circuit for applying the voltages to the common electrodes so as to solve the problem of deterioration in uniformity and stability of the voltages of the common electrodes. However, for a large-size LCD panel, this real-time adjustment manner hardly works.